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Other than the piston rings, “blow-by” gases can push the fuel oil past the rings and into the crankcase. [1] “Blow-by” gases are a mix of fuel oil and exhaust gases that push past the piston rings. Crankcase dilution is caused more when the lube oil is fresher. [3] Another cause of crankcase dilution is a slow or delayed injection ...
First, the lubricating oil in the engine will not adhere properly to the smooth surface, and in the absence of an oil film the resulting friction is increased. Secondly, while breaking in newly installed piston rings, a minute amount of wear must occur between rings and cylinder wall in order to seat the rings properly, and ensure a gas-tight seal.
Rings binding in the piston, usually due to a build-up of either combustion products or a breakdown of the lubricating oil, can cause engine failure and is a common cause of failure for diesel engines. [citation needed]
In most steam engine designs there is a short time at the end of the return stroke of the piston when all the valves are shut and it is compressing any remaining steam. Water can be introduced from the boiler or in a cold engine, steam will condense to water on the cool walls of the cylinders and can potentially hydrolock an engine.
An oil pump, a vane or gear pump powered by the engine, pumps the oil throughout the engine, including the oil filter. Oil filters can be a full flow or bypass type. In the crankcase of a vehicle engine, motor oil lubricates rotating or sliding surfaces between the crankshaft journal bearings (main bearings and big-end bearings) and rods ...
These blow-by gases, if not ventilated, inevitably condense and combine with the oil vapor present in the crankcase, forming oil sludge. Excessive crankcase pressure can furthermore lead to engine oil leaks past the crankshaft seals and other engine seals and gaskets. Therefore, it becomes imperative that a crankcase ventilation system be used.
Particles in the oil can also cause serious problems with oil pressure. After oil flows through the engine, it returns to the oil pan, and can carry along a lot of debris. The debris can cause problems with the oil pickup screen and the oil pump itself. The holes in the oil pickup screen measure about 0.04 square inches (0.26 cm 2). [6]
Dieseling (in the sense of engine run-on, and disregarding combustible gaseous mixtures via the air intake) can also occur in diesel engines, when the piston or seals fail due to overheating, admitting engine oil into the cylinder. A structurally failing diesel engine will often accelerate when the throttle is released, even after fuel ...